Methods of obtaining some of these features have been described in the literature. Some of these methods utilize bodies which might be used as a catalyst or a catalyst support body if made from a suitable material but which, according to the description in the literature, are used otherwise. Below, references will be given to literature describing catalysts as well as bodies having some of the above features without being catalysts.
U.S. Pat. No. 3,785,620 describes bodies consisting of corrugated lamellae which are proposed used as static mixers.
U.S. Pat. No. 4,296,050 describes packing elements for an exchange column made from a plurality of corrugated plates.
Sales pamphlets from Sulzer Brothers Ltd. describe bodies of similar form as the bodies of the U.S. Patents mentioned above, but in ceramic material, and propose to use them i.a. as catalyst support bodies.
U.S. Pat. No. 3,112,184 describes a method of making ceramic articles some of which have such characteristics as to fulfill the above features if made from a catalytic active material or used as support bodies. Such use is not, however, proposed in the description although it is stated that bodies of a somewhat similar configuration are used in such a way. It is proposed to use the articles for making heat exchangers transferring heat from streams flowing through some channels into streams flowing through others, but not to effect the heat transfer through a vessel wall.
EP Patent Specification No. 0 025 308 discloses a process and an apparatus for endothermic steam reforming of hydrocarbons. A catalyst in the form of a structure comprising a stack of profiled plates is described. The structure is spaced from the walls of the catalyst chamber and has passages angled to the overall direction of flow in the catalyst chamber causing a process fluid to flow alternatively through the catalyst and for a significant length through a space between the structure and the heated walls of the catalyst chamber. Due to this flow pattern, the heated walls will show exended and successive areas of high temperature and low temperature caused by prolonged heating of some of the fluid, and decreasing flow rate in different areas along the reactor walls resulting in low heat transmission, followed by massive flow of the process fluid leaving the catalyst with a reduced temperature due to the reaction inside the catalyst channels.
Thus, since the flow pattern according to the above mentioned EP-patent will not result in a uniform temperature distribution in the fluid entering the catalyst channels at a given level at the catalyst chamber, it is not possible to obtain a uniform catalyst utilization.
A very high transmission of heat from the walls of the catalyst chamber into the process fluid is particularly important when providing some of the heat for steam reforming of hydrocarbons by convective heat exchange between the process fluid and a flue gas in a heat exchange reformer. An essentially even temperature distribution along the heat transmitting walls is also of paramount importance for this process concept.
None of the previously proposed methods has fully overcome the problem of simultaneously obtaining (1) a very low pressure drop in the process fluid passing through the catalyst bed, and (2) a high heat transfer coefficient between the wall(s) of the catalyst chamber and the process fluid, and further (3) having uniform or essentially uniform temperature distribution along the heat transmitting wall(s), and (4) efficient utilization of the total amount of catalyst.